The present invention, in some embodiments thereof, relates to concealing of missing printing nozzles for inkjet textile printers and, more particularly, but not exclusively, to concealing missing nozzles in an inkjet textile printer that uses immobilization on the textile.
In inkjet printing in general, while using jetting nozzles, there is a common phenomenon most clearly visible on bright substrates as a bright thin line or gap. The phenomenon is the result of a failed nozzle.
In each printing head there are hundreds of nozzles. From time to time, nozzles stop functioning for various reasons such as clogging, electrical failure etc. A missing nozzle may appear very meaningfully on the image as a strike or a gap. This is even more severely noticeable when the image is built of a solid color area.
Textile digital printing technology may use an immobilization mechanism in which an immobilization agent is jetted through printing nozzles in immobilization phase. The immobilization phase may be carried out shortly before, during or immediately after application of the printing ink. The immobilization agent within an immobilization fluid interacts with color ink drops that are also jetted from inkjet heads. The immobilization agent prevents the color ink drops from bleeding into the fabric or flowing into another color droplet. In addition, the interaction between the color ink drops and the immobilization fluid phase prevents the color ink drops from spreading on the fabric surface. The result is a sharp image and intense image color.
Accordingly, immobilization fluid drops are jetted on each specific location that color ink drops are planned to be located in the same way that the actual printing is carried out. In practice an image file separation which is the sum of all color file separations is prepared and then printed onto the fabric as an immobilization phase.
Color ink drops that are not immobilized tend to bleed into the substrate and spread. The final dot diameter without immobilization is much larger than same drop which is immobilized by the immobilization phase, leading to an even more noticeable effect of the bleeding than there would be without immobilization.